In the design and construction of fluid handling machines of the centrifugal type, especially glandless gap-tube pumps and compressors in which a shaft axial bearing operates in a bath or supply of lubricant (including, in particular, the pumped fluid), a problem is presented by the axial thrust forces, often of considerable magnitude, which are exerted upon the bearing by the impeller or impellers acting through the shaft.
In the past, various bearing designs, have been introduced to provide proper accommodation of the high axial thrust forces. Many of those designs that are relatively simple have been found to be susceptible to excessive wear. Other designs are disadvantageously more elaborate and expensive. Further, with many of these designs, proper lubrication is critical, and this requires additionally complex lubrication systems.